As a method of forming a protective film for a medium such as a hard disk, there is CVD using a reactive gas such as C2H2 of C2H4. In recent years, to shorten the spacing distance or head floating amount between a magnetic read head and the magnetic recording layer of a medium and improve the drive characteristic, a protective film of carbon or the like deposited on the magnetic recording layer also needs to be thinner.
However, the thinness of a carbon protective film deposited by CVD is said to be limited to 2 to 3 nm because of its characteristic. As a technique that replaces CVD, a deposition method (Vacuum Arc Deposition) using arc discharge, which can form a thinner carbon protective film, has received attention. Since the vacuum arc deposition can form a hard carbon protective film with a small hydrogen content as compared to CVD, it may be possible to reduce the film thickness to about 1 nm.
For example, Patent Document 1 describes a deposition apparatus including a striker configured to form an arc spot on a target and make the target emit target ions and electrons by arc discharge, an anode unit configured to maintain an arc, an anode coil configured to form a flow of electrons between the target and the anode unit, and a filter unit configured to guide the target ions and electrons to a process chamber.